This node setup allows procedural pole, tempered, desert on local Z axis based on cursor location (it should be at the center). So you can rotate, scale move in object mode without any problem.
The Object Texture Coordinates Outputs -1 to 1 coordinates for all local axis (origin=0, so the origin has to be at the center of the object). Then we separate XYZ vectors because we want the Z coordinates only. Using the Absolute node will give us a mirrored 1/0/1 along local Z.
So now we have coordinates on Z that are 0 in the middle and 1 at each pole.
The 1st mix node is controled by a 'Greater Than' Node 0.2 so the material will use 'Desert' input from 0 to 0.2 and 'Grass' if Z coordinate is greater than 0.2.
The 2nd mix node will use the 1st mix and mixes it with 'Ice' if Z coordinate is greater than 0.8.
To control where the limits are, just change the 'greater Than' values (0-1).
But this setup will work only if your mesh sphere has a size of 2 units (default, size of the object doesn't matter).
So we want to fix this using the Generated coordinates.
The generated coordinates will give a 0/1 on each local axis, no matter where is the origin or the size.
Now we modify the coordinates with a 'subtract' 0.5 so we have -0.5/0.5, 'multiply' 2 to make it -1/+1 as before. This time the spere can be resized in object or edit mode, nothing will change!